1. Field of the Invention
This invention relates to machine tools, and, more specifically, to milling machine head assemblies and to power transmissions which may have wider application than in the machine tool field.
2. Information Disclosure Statement
There are known, of course, heavy industrial milling machines comprising a milling head, which carries the tool bit or bits and which is provided with heavy drive motor, and in which the entire head is moveable vertically when the machine is in the normal upright mode of operation and is also rotatable about a horizontal axis. That kind of machine is also provided with a heavy duty worktable to which work pieces can be attached and which can be moved by feed screws in X and Y directions in a horizontal plane or in the plane to which the table is adjusted.
At the other end of the scale, there are light-weight milling machines such as are used by model makers in which the head also embodies the drive motor and is movable in a manner similar to that in the heavy machine, but because the machine is designed for machining of small, light parts, and may be used indoors on a table top worksurface, the machine must be kept as light as possible. Therefore, a very light, lower rated motor must be used, since that motor in prior-art machines moves with the head in operation. It has been found that in fact the available light weight machine is too fragile for the majority of operations which it has to perform.